poor wireless transfer rates for file copy

[cdmackay]

[I ask this here, in the CF forum, since there is perhaps enough different about CF (e.g. wireless drivers) to make it CF specific]

I'm getting very poor transfer rates when copying files over wireless, e.g. less than 1Mbit/sec, even though the wireless connection rate is allegedly 100 times that.

I'm using an Edimax EW-7711UAn dongle (at 2.4GHz), which works perfectly, functionally at least. But I struggle to get more than 1Mbit/sec when copying files to/from the PC.

On the Humax, cmdline iwconfig reports between 40--135 Mbits/sec for the connection rate, and my wireless router confirms those figures (which fluctuate). I don't expect to get near that in practice, of course, for real file transfer, given the usual overheads, but I might expect to get near half that, perhaps?

Initially, I was using rsync over SSH (with SSH compression disabled), but thought perhaps that ssh was too much for the Humax cpu. But a wget of a file from my PC, over plain HTTP, fared no better, still around 1Mbits/sec (although perhaps slightly better than rsync/SSH).

So, should I be surprised?

The Humax isn't all that accessible, so I can't easily move it nearer the router to see if there's a massive improvement. But if the Humax, and the router, are reporting connection rates in the many tens of Mbits/sec, shouldn't I hope for better than 1Mbits/sec for real transfers?

Anything obvious I should test (other than the above, which I will try to arrange)?

thanks much indeed.

 

[MymsMan]

Have you tried a wired connection to your router to determine whether or not it is specifically related to the wi-fi connection?

My Humax is connected by cable to the router and by wireless from router to PC and I find viewing with VLC problematical with frequent buffering delays but I haven't done any real investigation to measure speeds or debug the problem.

A couple of quick transfers using FTP show I can get 5.9 MiB/s using wireless to PC and 10.7 MiB/s using cable to PC

 

[cdmackay]

Thanks much. No, there's no easy wired access to the TV area, hence my using wireless.

I will see if I can string a long wire, for a short test, without arousing the attention of the better half

Just to clarify, please, you are getting 5.9/10.7M Bytes, or bits / sec? I'm guessing the former?

thanks again...

 

[johnb]

I've experimented with various methods and found, for a wired network:

Running rsync/ssh on the Humax to copy files to a ubuntu server is so slow as to be useless.

Running rsync/ssh on the ubuntu server to pull the files from the Humax is faster but still very slow.

In the end the solution that works for me is to install NFS on the Humax (so I could set up a share on the ubuntu server) or install Samba on the Humax which enables you to set up a share on either a linux or windows box - then to run rsync (on the ubuntu server) copying the mounted share. This gave around 10.4 MiB/sec for NFS or around 9.4 MiB/sec when using a Samba share. I guess the increased speed is because rsync doesn't use ssh when copying locally.

Do you have a strong wireless signal strength at the Humax? I ask because, although I might be wrong (I often am), I have the impression that wireless speeds can drop off very significantly once the signal strength drops below a certain level.

 

[cdmackay]

thanks; I installed the nfs-utils pkg, to make the Humax an NFS server, and mounted it NFSv3 on my PC client.

Managed less than 1MB/sec. Am getting 60%--70% wireless strength. Odd.

I'll try some wired tests, and get the Humax out on the bench where I can be sure the wireless is getting a good signal.